Improvement in files



A. HYLAND.

Improvement in Files.'

Patented May 16;'1871.

- tintin atca AMAsA HYLAND, orHINeHAM, MASSACHUSETTS.

Letters Patent'No. 114,824, dated May 16, 1871.

IMPROVEMENT IN I=II.Es.-

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern Be it known that I, AMAsA HYLAND, of Hingham, in the county of Plymouth and State of Massachusetts, have invented an Improvement in Files, of which the following is a full, clear, and exact description, reference being had to the accompanying draw- `ing making 'a part of this specification, in which- Figure l is aA perspective view of the teeth cfa por- Figure 4, a plan (enlarged) of a portion of the upper side of my improved hle.

Figure 5, a plan (enlarged) of a portion of the upper side of an ordinary three-cornered iile.

Three-cornored files for sharpening saws,'&c., have heretofore been provided with a right-hand cut 7?- that is to say, the cutis 'made from left to lright relative to the point.

To the use of this description of files there is, however, `the following objection In the ordinary process of filing the operator naturally exerts a greater pressure from him than toward him, or upon the tooth of the saw to the right ofthe iile than on the saw-tooth onthe left of the tile, which circumstance, together with the fact of' theteeth ot'- the tile on the left side pitching down toward the point, and'lhe teeth ofthe h'le on the right side'pitching down toward the tang, causes the tooth of the saw on the right ot' the file to he .tiled ot? faster than the saw-tooth on the left, and consequently the alternate teeth of the saw have their tops or'points worn down, which reduces their length, -and the saw is uneven, not so effectivesl and sooirbecomes useless.

To overcome the above-mentioned diiculties is the object of nIy invention, which-consists iII athree-cornered tile provided with a left-handcu-tthat.is, a series of teetlnt'he direction of which is from right to left relative to the point, by which arrangement the.' tendency of the operator to press the iile from him and cut into and wear od the point otthe tooth of the saw to the right ofthe file is connteracted hy the tendency of the teeth 'ot' the die on that side to ride up instead of working down against the said tooth ot' the saw, while at the same time, although the inclination of the le-teeth on the left side tends to cause them to work down into the saw-tooth on the left, this tendency is also counteracted by the le bearing more lightly thereon than on the saw-tooth `to the right of the file, and the result is that both sides of contiguous saw-teeth are equally sharpened and reduced, instead of unevenly reduced, as before, and the saw is uniformly and gradually cut away by the operation of ilin n Tia; enable others skilled iI1 the art to understand and use my invention, I will proceed to describe the manner in which I have carried it out.

In the said drawing-- A represents a portion of a saw whose teeth a. b are to be lfiled by moving a three-cornered file, B, provided with a left-hand cnt (see figs. 2, 3, and 4) in the notch c, between the side 2 ofthe saw-'tooth a., and the s ide l ofthe saw-tooth b.

` The iile bears harder on the side 1 of the saw-tooth l) than on the side 2 ofthe saw-tooth a, but the pitch or cut ofthe teeth ofthe iile on the right-hand side 3 being from its lower edge 4 outward toward the point of the le up to its upper right-hand edge 5, (see tig. 2,) and the pitch ot' they teeth of the le on its left-hand side 6 being reversed, or from the lower edge 4, in towardv the tang to its upper left-hand edge 7, (see iig. 3,) the tendency to press harder on the right-hand-saw-tooth b is offset by the file readily rslippingr up thereon, and the tendency of the operator to bear lightly on the side ofthe saw-tooth a on the left is counteracted by the tendency of the teeth of the h'le on thelel't sidev to run down and hold harder thereon, the result being to evenly sharpen and equally reduce the opposite sides of every tooth, and the entire series of the saw-teeth is gradually and uniformly reduced in contradistinction to the irregular teeth of a saw sharpened by the ordinary right-handout file C, (see tig. 5,) as heretofore.

Claim.

What I claim ns my invention, and desire to secure by Letters Patent, is-

A three-cornered tile having a left-hand cut, suhsta-ntially as and for the purpose set forth.

Witness my hand this 1st day of November, A. D. 1870.

' `AMASA HYLAND.'

Witnesses:

N. W. S'rnAnNs, L. E. lSATcnELLEn. 

